xx   xx   xx   xx  xx   x   x



.l- A n D R O .r. .N A T S H. R.

OVEN

Filed April 27, 1932 2 Sheets-Sheet 1 I I Ill THEIRAITORNEXS 2 Sheets-Sheet 2 `-July 9, 1935- R. H. s'rANlFoRD Er AL OVEN Filed April 27, 1932 fabel-' Patented July 9,Y 1935 "i UNITED STATES y`PTA-'1fr.1vr *cerise i The present invention relates to ovens and embodies, more specifically, an improved gas oven for bakeries wherein the heat of the oven chamber is derived'from two independent sources, each of which may be separately controlled, and' the products of combustion of which are directedto suitable exhaust stacks in such fashion that the full effect of each heat source is obtained. v

In gas ovensnow available the heat which is supplied to the oven is derived eithervfrom a single or a plurality of sources, such as agas aine, the products of combustion of whichv are not .definitely directed in any particular course -throughthe oven to an exhaustY stack. Consequently considerable diflculty has ,been experi:- enced Vin providing a .uniform Vtenlperature throughout the oven and in varying such temperatures between desiredl limits effectively..

`Hence the factorof oven controllabilityVupon which uniformity of bake is dependent, has not heretofore been satisfactorily met.` z

In this connection, thepresent invention contemplates the provision of Vimproved controllability by directingl the products 4ofc-combustion Vfrom separate heat sources. through heat paths, each of which has its own exhaust stack.V -At each heat source, the ventilation of the ovenvis controlled by admitting the correctA amount of secondary air, ,wherebywgreater flexibility of heat regulation throughout the` oven is aiiorded.,Y With vof the oven may be decreased. Y Y y e Greater economy of operation israttained by thepresentV invention by reason of the elimina:- tion of forcedidraft as well as becauserof a greater workable hearth area andfless oven volume for a given capacity. The secondary air 4control enables theA amount of air supplied to be definitely controlled, thus eliminatingtheloss of heat heretofore required to. heat the excess air 4necessarily supplied.

- Further improvedcharacteristics will appear hereinafter and the present invention has ioran object the provision of an improvedform of oven in `which the possibility of explosion lduring` operation is reduced to an absolutevminimllm. A further object of the invention is to provide a gas oven wherein an exhaust. damper and 'main gas supply valve `arefeffectively controlled to insure proper ,coordination` therebetween Ato prevent ,explosionswithin the oven. I i

VA furthercobject ofmthe invention isto VVrovide 4 an improved control mechanism Vfor,V gas 'ovens vwhereby theexhaust damperLandmain gas sup'- ply larel interlocked in suchfashionthat AEthe the operationof the burner. greaterlexibility of heat-regulationthe'volume f main gas supply may "be opened only whenthe exhaust damper is'ope'n. f v i vA further object ofthe invention is'to provide 'afgas ovenl provided with al plurality of heat sources,` the 'gases V:from each heat Vsource being :separately directed-to exhaustfducts. y A4 further ob'ject ofi'the invention is to provide a gas ovenfhavinga plurality of independent heat sourcesjthe Vgases from the respective heat sourcesbeingeiiectively directedrinto the oven'charnber, 'or in Vdperative relation thereto,

Vto maintain a uniform desired heat therein;l

Afurther object' of the'invention isrto provide a gas oven having top and bottom heat sources, each heat source'beig separately controlled and the iow of gas-theretrom'b'ei'ng separately directed into operative' relation" with respect to the oven'Y chamber Vand 'to exhaust ducts.

A further object of the invention is to'provide 'a gas ovenfhaving a plurality of separate heat sources; thefovvof gases from which are controlled independently,properly located top and bottom" heatcooling`"dampers being provided to control theftemperatureof lthe oven effectively. A further object of, the invention is to provide an improved heatesiipply' mechanism for gas 4'ovens wherein a secondary air supply Vis provided ,for a burner,y the quantityfof airsupplied thereby rbeing automaticallyvv regulated in accordance with lfurtherobjectoff'the invention is to provide afgasV oven "wherein a plurality 'of heat sources areprovid'ed and means is provided to direct the hotgasesfromtlie sources into0 the oven in such `fas'lnionfthat the temperature within the oven fchamberisfsubstaritially uniformfat all points therein' and wherein Y means `-is `Vprovided for efectivelyvregulating such temperature between desired limits, *thje'v'oven structure being airtight and'fia' compact nature. l

l `Further objects, n ot-V s pecioally n enumerated above; will/be apparent as thejinvention is described in 4greater'detail'iin connectionwith the accompanying drawings,` wherein:

, s-Fig'ure l'isa view -in vertical section, taken in aj-plane passing through the axis of an oven construct'edin accordance with thepresent invention and showing the` plurality of heat sources from which thev oven'heat is derived, as well as the lducts, dampers and controlling mechanism therefor. j Y" "Figure 2 is an enlarged View showing the control mechanism' for thefexhaust damper and main gas supply mechanismof the present invention. Figure'isa segmental view in side elevation showing the control mechanism of Figure 2, the view being taken from the left, as viewed in Figure 2.

Figure 4 is a segmental view in horizontal section, looking down upon a burner constituting one of the heat sources of the present invention, this view illustrating the control mechanism for the secondary air supply device.

Figure 5 is an enlarged segmental view, similar to Figure 1, showing the secondary air supplying structure in detail.

With reference to the accompanying drawings,

the oven structure embodyingthe present invenfv tion will be seen to include a rotatable hearth I which is mounted upon a shaft Il, journaled at I2 in the oven foundation I3. A step bearing I4 is provided to carry the Weight of the hearth While a bearing I4 is provided to journal the top of shaft II. A suitable driving mechanism I5 affords a means for rotating the shaft II and hearth I0. A

Arms I6 may be provided Ito brace the hearth and enable the same to be mounted Vand sup- Aported effectively upon the shaft II, the hearth being formed with an apron baille I1 centrally thereof to form avertical duct I I through which heat may flow from a supply duct I 9 in the oven foundation. The apron baille4 I1 may be mounted upon the shaft I I by means of arms 29 and a lower heat trap 2| is provided between the oven foundation and apron baille I1 to prevent heated gases from the supply duct I9 from passing into the chamber below the hearth I0. This lower heat trap maybe formed of an annular stationary member which is U-shaped in cross section and mounted in the ovenk foundation I3, the lower extremity of the apron baille I1 being received therein to afford an effective baille and obstruction against fluid flow therethrough.

A burner 22 is provided at theentrance to the duct I9 and constitutes a heat source for supplying heat to the chambervabove the hearth through the duct I9 and apron baille I1. Secondary air ducts 23 are formed in the oven foundation, the flow of air being controlled in a manner described hereinafter.

Above the rotatable hearth I0, an oven crown 24 is provided, the heated gases from the duct I8 flowing upwardly-against the crown 24 and being directed downwardly therefrom onto the hearth I0. Top heat flues 25 areformed in the oven crown and are preferably spaced atv 90 therein, whereby heated gases from the chamber above the burner may be removed at four spaced points at the sides of the oven. i Iny orderthat the full effect of the top heat source may be felt in all parts of the chamber above the hearth, the entrances 26 to -the flues 26 are formed at substantially the level of the hearth. In this fashion, the heated gases will be directed downwardly against the hearth before flowing Into the exhaust flues. The four or moreY exhaust flues 25 preferably lead to a vertical stack 21 into which the heated gasesV flow from the nues. An exhaust damper 28 may be mounted slidably in the stack to control the flow of gases therethrough, the damper 28 being operated in a manner described hereinafter. f

Beneath the hearth III and the chamber between the hearth and crown 24 which constitutes the baking chamber, a bottom heat chamber 29 is provided. This chamber is sealed from the baking chamber by means of a, cylindrical skirt 30 which is formed upon the hearth I0 and which isreceived within a cooperating cylindrical seal.-

ing member 3|. The bottom heating chamber 29 is provided with a burner recess 32 in which a plurality of burner units 33 are mounted, longitudinal baflles 33' being provided between adjacent burners to facilita-te the regulation of secondary air thereto. These burner units are supplied with gas from a gas pipe 34 which is connected to a main gas pipe 35. Each burner unit 33 is provided with a valve and valve operating handle 36 to control the'flow of gas from the pipe 34 tothe respective burner unit, and the valve spindle has secured thereto a gear sector 31 which is adapted to engage teeth 38 formed in a plate 39 which is slidably mounted in brackets 40 beneath the respective burner units 33.

The oven foundation I3 is formed with a recess 4I beneath the burner units 33 and this recess receives the plates 39. Secondary air ducts 42 communicate between the burner recess 32 and the recess 4I and thus provide a source of secondary air for the respective units. Plate 39 is formed with a plurality of apertures 43, corresponding in number and position to the ducts 42, whereby the secondary air ducts are opened simultaneously with the opening of the respective valve units 36.

The heated gases from the burner unit 33 flow upwardly against the under surface of the rotatable health I0 and through the bottom heat chamber 29 to an outlet duct 44 which communicates with a bottom heat stack 45. The duct 44 ispreferably placed adjant the bottom ofthe chamber 29 to build up a depth of heating gas practically equivalent to the bottom heat cham-4 ber 29. In as much as the duct 44 is diametrically opposed to the burner units 33, the heated gases from the latter must necessarily flow entirely through the chamber 29 before being discharged, thus utilizing a maximum amount of heat therefrom. ,Y

In order that the temperature of the oven may be effectively and quickly controlled, top and bottom heat cooling dampers 41 and 48 are provided, respectively. These dampers may be of usual form and are actuated by rods 49 and 56, respectively, the rods being connected to bell crank levers 5I and 52, respectively. Bell crank 5I is actuatedby an operating rod 53 having a handle 54 while a bell crank lever 52 is actuated by a rod 55 upon which a handle 56 is formed. When dampers 41 and 48 are opened, cooling air is admitted into the top and bottom chambers to effect the rapid cooling thereof. In as much as, during the normal operation of an oven, baking operations requiring widely varying temperatures'may be met with, the cooling damper construction is of considerable importance in as much as such baking operations may take place successively without any substantial interval of time to enable the oven to be cooled to a desired temperature. In order that the danger of explosion may be minimized and even entirely eliminated, the exhaust dampers 28 and 46 are controlled by a mechanism which is interlocked with the valve in the main gas line. To this end, control rod 51 is mounted upon the oven and connected to the dampers 28 and 46. The rod is provided with an operating handle 58 ,which has a fin 59 formed thereon. The fin is 'provided With a slot 60 which is adapted to receive a sector plate 6|, mounted upon the spindle of a valve 62 in the main gas line 35. An operating handle 63 is provided on the spindle 62 and the Sector plate 6I is formed with a boss 64 atomic The foregoing mechanism, by providing the the oven chamber isI efficiently and eiectively controlled. VThis heat is uniform throughoutall portions of the, chamber and is eiiectively regulated by means of the dampers il and 48. .Each burner, together with its secondary air supply,

-is separately controlledk and theV temperatures *constructions .There is no'forced ventilation necessary andthe oven chamber, asiwell as heating chambers and ductsare air-tight duringoperation. This tightness of the oven holds the heat and decreases the heatloss during the periods that the oven is shutdown. Since the sec-V ondary air issupplied to all portions of each burner uniformly, proper combustion is insured along the entire length of the burner.

It will be seen that thel invention is not limited to the particular type of fuel utilized nor to Vthe specific type of oven although to facilitate the description thereof, arotary hearth type of oven has been shown.

While the invention has been described with specific reference to the accompanying drawings, it is not to be limited, save as dened in the appended claims.

We claim as our invention;

l. An oven,a plurality of independent heat sources therefor, an `oven hearth in the oven, one of said heatsources applying direct heat below the hearth and another of the heat sources being spaced'fromthe oven, a flue from the second named source to 'the oven above the hearth, whereby the heat sources independently apply direct heat to the bottom and top of the hearth in independent heat paths, and means including the hearth to form a gas-tight b-aiiie between the region above and below the hearth to maintain the heated gases from the independent heat sources in independent paths during the travel thereof through the oven, whereby the condition of the heated gases discharged from the separate heat paths in the oven willindicate the condition of the heated gases in the independent paths in the oven.

2. An oven, a plurality of heat sources therefor, a movable oven hearth in the oven, means to direct heated gases from one of the heat sources over and in communication with the hearth, means to direct heated gases from another of the sources in an independent path beneath and in communication withthe hearth andmeans including the hearth to form a gastight baie between the region above and below the hearth.

3. An oven, a hearth in the oven, a crown over the hearth, means to direct heated gases between the hearth and crown and in direct communication therewith, separate means to direct heatedgases beneath. the hearth and inr direct communication therewith, and means including the hearth to form a gas-tight baille between the region above and below the hearth and to maintain the heated gases from the Vseparate `means in separate paths until discharged from the oven, whereby the condition of the heated ,in a path independent ofthe gases separately discharged from the oven will indicate the condition of the heated gases in the `separate paths in the oven. plurality of heat sources, results in an oven Y. construction `by means of -which the heat within 4. An oven, a movable hearth in the oven, Va

crown Vover the hearth formingwith the hearth Y an upper heating chamber, said hearth forming rate means to directY heat through the lower chamber, and means to maintain ,the -heat sodirected in separate paths including-a heat trap between the hearth andl oven. Y

5; An oven, a hearth in the oven, a crown over the hearth, means to direct heat between the Ahearth and crown, .a i'lue having an opening ad- -jacent the level or" hearthfor receiving heated gases `from between the hearth and crown-and separate means to direct heat beneath the hearth path of heat between 4the hearth and crown.

6. An oven, a hearth in the oven, a` crown over the hearth., a plurality ol heat sources in the Yoven beneath the hearth, said hearth forming separate chambers above and below the hearth, means to direct heated gases from one of. the sources direct through the entire chamber beneath the hearth, and means to direct heated gases directly in an independent path from other of the heat sources through the entire chamber above the hearth.

7. An oven, a rotatable hearth in the oven, a crown over the hearth forming a chamber thereabove, a chamber below the hearth, sealing mea-ns between the chambers above and below the hearth, separate heat sources, means to direct heat from one of the sources centrally of the hearth into the chamber thereabove, and means to direct heat from another of the sources independently of the first heat through the chamber beneath the hearth. i

8. An oven, a rotatable hearth in the oven, a

crown over the hearth forming a chamber thereabove, a chamber below the hearth, separate heat sources, means at the periphery of the hearth to seal the upper and lower chambers apart, an apron b'aiiie on the hearth centrally thereof forming a duct to the upper chamber, a heat source communicating with the lowerchamber, and a heat source and duct communicating with the apron baifle duct.

9. An oven, a hearth, a burner in the oven, a stack through which' spent gasesare discharged, a damper in the stack, a fuel supply having a control valve, and an interlocking mechanism between the valve and the damper to' prevent opening the control Valve when the damper is closed.

l0. An oven, a hearth, a burner in the oven, a stack through which spent gases are discharged, a damper in the stack, a fuel supply having a control valve, separate manually actuated devices for actuating the valveiand damper, and means `toprevent vthe opening of the valve when the rality of heat sources therefor, means to direct heated gases from the sources in separate'paths through the oven, andseparate means to introduce coolingY gases into the baking chamber.

13. An oven, a plurality of heat sources therefor, an oven hearth in the oven, means to direct heated gases from one of the heat sources over the hearth, means to direct heated gases from another of the sources n an independent path beneath the hearth, and separate means to introduce cooling gases into the respective paths one of said means introducing cooling gases directly into the baking chamber.

14. Anv oven, a rotatable hearth in the oven, a crown over the hearth forming a chamber thereabove, a chamber below the hearth,'sealing means between the hearth and oven at the periphery of the hearth, a central duct passing through the lower chamber sealed therefrom and communicating with the upper chamber, separate heat sources, means to direct heat from one of the sources through the duct into the chamber thereabove, and means to direct heat from another of the sources independently of the rst heat through the chamber beneath the hearth.

15. An oven, a plurality of independent heat sources therefor, a movable oven hearth in the oven, one of said heat sources applying direct heat below the hearth and another of the heat sources being spaced from the oven, a flue from the second named source to the oven above the hearth, whereby the heat sources independently apply direct heat tothe bottom and top of the hearth in indepnedentl heat paths, and means including the hearth to lform separate heat chambers and flue passes of the region above and below the hearth, whereby the application of direct heat to such regions may be effectively and independently controllable.

16. An oven having a baking chamber and a hearth therein, a bottom heat chamber beneath the hearth, a ue through which gases may be discharged from the bottom heat chamber, a plurality of burners in the bottom heat chamber, means to supply independent secondary air to each of the burners and. means to vary the secondary air to the respective burners independently.

ROBERT HM STANIFORD. CARLTON W. ROLL. 

